Abstract: A reflection-mode photoacoustic endoscope includes a tube, a light source configured to emit a light pulse suitable for photoacoustic imaging, an ultrasonic transducer configured to detect a response signal, and a light and acoustic reflector rotatable relative to the tube.

Abstract: A reflection-mode photoacoustic endoscope includes a light source configured to emit a light pulse, a signal detection or transmission unit configured to detect or emit an ultrasonic pulse, and a rotatable reflector. The rotatable reflector is configured to reflect at least one of the light pulse and the ultrasonic pulse into a target area of an object, and reflect a response signal to the signal detection unit. The response signal is one of a photoacoustic wave generated by the object responsive to the light pulse and an ultrasonic pulse echo generated by the object responsive to the ultrasonic pulse.

Abstract: A method for obtaining a 3-D OR-PAM image of microvasculature within a region of interest of a subject is provided. The method includes: focusing a first light pulse at a first depth beneath a first surface position within the region of interest; receiving a first PA signal in response to the first light pulse; focusing a second light pulse at a second depth beneath the first surface position within the region of interest; receiving a second PA signal in response to the second light pulse; and forming the 3-D OR-PAM image by combining the first PA signal and the second PA signal.

Abstract: A method for determining a ratio of hemoglobin absorption within a biological tissue using a handheld device is provided. The method includes focusing at least one light pulse into a predetermined area inside an object using at least one excitation wavelength, wherein a fluorescence signal is based on at least a local excitation optical fluence and properties of fluorophores in the predetermined area. The method further includes receiving a photoacoustic signal emitted by the object in response to the at least one light pulse, the photoacoustic signal being a product of the local excitation optical fluence, an optical absorption coefficient of hemoglobin, and an acoustic detection sensitivity. The method further includes determining the ratio of hemoglobin absorption based on a hemoglobin absorption coefficient that is based at least partially on the fluorescence signal and the photoacoustic signal.

Abstract: A photoacoustic medical-imaging device includes a wavelength conversion assembly (108) configured for outputting laser pulses at a targeted wavelength. It also includes a photoacoustic probe configured for acoustic coupling to a patient, for directing the pulses, and for acquiring, in response, radiofrequency data for photoacoustic imaging. It may include an optical fiber bundle (120) that comprises an optical fiber having an input end, and be configured for illuminating, with a homogenous beam, so as to conform to an acceptance angle (160) of the fiber at that end. It may also include a light collimator, and a diffuser for receiving the outputted laser pulses from the collimator. The diffuser may be configured for spreading a focus of the pulsed light (148) over an input aperture of the bundle to equalize the light received by different constituent optical fibers of the bundle. The assembly may include a dye cell (132), and may reside in the probe.

Abstract: Systems and methods of reconstructing photoacoustic imaging data corresponding to a brain of a subject through a skull of a subject utilizing a reconstruction method that incorporates a spatial model of one or more acoustic properties of the brain and skull of the subject derived from an adjunct imaging dataset.

Abstract: A probe for use with an imaging system, including a scanning device configured to receive a first light beam from a light source, a beam-divider configured to split the first light beam into a plurality of second light beams, and a focusing device configured to focus each of the second light beams on respective locations in an object of interest is disclosed.

Abstract: A probe for use with an imaging system, including a scanning device configured to receive a first light beam from a light source, a beam-divider configured to split the first light beam into a plurality of second light beams, and a focusing device configured to focus each of the second light beams on respective locations in an object of interest.

Abstract: The present disclosure is directed to methods of non-invasively imaging cell nuclei. More particularly, the present disclosure is directed to methods of imaging cell nuclei in vivo using ultraviolet photoacoustic microscopy (UV-PAM), in which ultraviolet light is used to excite unlabeled DNA and RNA in cell nuclei to produce photoacoustic waves.

Abstract: A single-RBC photoacoustic flowoxigraphy (FOG) device is described that delivers laser pulses of two different wavelengths separated by a pulse separation period of about 20 ?s. This separation period is sufficiently brief to enable pulses of two different wavelengths to illuminate the same single moving RBC. The acoustic signals elicited by the single RBC in response to the laser pulses of two different wavelengths may be analyzed using pulse oximetry methods similar to those described herein above to simultaneously determine a variety of functional parameters.

Abstract: A method for determining a ratio of hemoglobin absorption within a biological tissue using a handheld device is provided. The method includes focusing at least one light pulse into a predetermined area inside an object using at least one excitation wavelength, wherein a fluorescence signal is based on at least a local excitation optical fluence and properties of fluorophores in the predetermined area. The method further includes receiving a photoacoustic signal emitted by the object in response to the at least one light pulse, the photoacoustic signal being a product of the local excitation optical fluence, an optical absorption coefficient of hemoglobin, and an acoustic detection sensitivity. The method further includes determining the ratio of hemoglobin absorption based on a hemoglobin absorption coefficient that is based at least partially on the fluorescence signal and the photoacoustic signal.

Abstract: A confocal photoacoustic microscopy system includes a laser configured to emit a light pulse, a focusing assembly configured to receive the light pulse and to focus the light pulse into an area inside an object, an ultrasonic transducer configured to receive acoustic waves emitted by the object in response to the light pulse, and an electronic system configured to process the acoustic waves and to generate an image of the area inside the object. The focusing assembly is further configured to focus the light pulse on the object in such a way that a focal point of the focusing assembly coincides with a focal point of the at least one ultrasonic transducer.

Abstract: Imaging systems, probes for imaging systems, and methods for noninvasive imaging are disclosed. In one example, a probe for use with an imaging system includes a slit configured to spatially filter a light beam from a light source. The probe includes a focusing device configured to cylindrically focus the spatially filtered light beam into an object, and an ultrasound transducer array configured to detect a photoacoustic signal emitted by the object in response to the cylindrically focused light beam.

Abstract: A probe for use with an imaging system, including a scanning device configured to receive a first light beam from a light source, a beam-divider configured to split the first light beam into a plurality of second light beams, and a focusing device configured to focus each of the second light beams on respective locations in an object of interest.

Abstract: A reflection-mode photoacoustic endoscope includes a light source configured to emit a light pulse, a signal detection or transmission unit configured to detect or emit an ultrasonic pulse, and a rotatable reflector. The rotatable reflector is configured to reflect at least one of the light pulse and the ultrasonic pulse into a target area of an object, and reflect a response signal to the signal detection unit. The response signal is one of a photoacoustic wave generated by the object responsive to the light pulse and an ultrasonic pulse echo generated by the object responsive to the ultrasonic pulse.

Abstract: Noninvasively imaging biological tissue using a handheld device. A light pulse is focused into a predetermined area inside an object using a flexibly mounted cantilever beam, acoustic waves emitted by the object in response to the at least one light pulse are detected by a transducer, and an image of the predetermined area inside the object is generated based on a signal generated by the transducer representative of the acoustic waves.

Abstract: A method for measuring a fluid flow includes employing small light-absorbing particles as tracers that flow at the same speed as the fluid, measuring the photoacoustic Doppler shifts of the photoacoustic signals produced by these tracer particles, and determining, from the measurements, information about the flow including one or more of the flow speed, flow profile, and flow direction.

Abstract: A confocal photoacoustic microscopy system includes a laser configured to emit a light pulse, a focusing assembly configured to receive the light pulse and to focus the light pulse into an area inside an object, an ultrasonic transducer configured to receive acoustic waves emitted by the object in response to the light pulse, and an electronic system configured to process the acoustic waves and to generate an image of the area inside the object. The focusing assembly is further configured to focus the light pulse on the object in such a way that a focal point of the focusing assembly coincides with a focal point of the at least one ultrasonic transducer.

Abstract: A method for measuring a fluid flow includes employing small light-absorbing particles as tracers that flow at the same speed as the fluid, measuring the photoacoustic Doppler shifts of the photoacoustic signals produced by these tracer particles, and determining, from the measurements, information about the flow including one or more of the flow speed, flow profile, and flow direction.

Abstract: The present invention provides a method, system and apparatus for reflection-mode microscopic photoacoustic imaging using dark-field illumination that can be used to characterize a target within a tissue by focusing one or more laser pulses onto a surface of the tissue so as to penetrate the tissue and illuminate the target, receiving acoustic or pressure waves induced in the target by the one or more laser pulses using one or more ultrasonic transducers that are focused on the target and recording the received acoustic or pressure waves so that a characterization of the target can be obtained. The target characterization may include an image, a composition or a structure of the target. The one or more laser pulses are focused with an optical assembly of lenses and/or mirrors that expands and then converges the one or more laser pulses towards the focal point of the ultrasonic transducer.